The benefits of routine oil changes in an internal combustion engine are well known. Routine oil changes have been shown to increase engine life and performance. With repeated prolonged use, motor oil builds up suspended particles, metallic and non-metallic, from the abrasive and adhesive wear of engine parts against one another and from products of incomplete combustion and improper air intake. The particles in turn cause abrasive wear of the engine bearings, piston rings and other moving parts and the reduction of the motor oil lubricity as various additives and lubricating components become depleted. This adversely affects engine performance and if left unchanged can destroy or cripple the engine performance. It is recommended by at least one oil manufacturer that the level of total solid concentration be limited to levels below 3.0%.
To obtain satisfactory engine performance, and maintain solids concentration levels in the motor oil lower than the recommended 3.0%, changing the motor oil in an internal combustion engine is necessary. In currently designed vehicles, the oil pan serves the purpose of a reservoir for circulation of engine oil. Engine lubrication is generally accomplished through a gear-type pump. Oil from the pump passes through the oil filter before going to the engine oil galleries from where it provides lubrication to the various engine components.
To remove the contaminated oil, the drain plug, generally located in the lowermost region of the oil pan, is opened. The spent oil containing suspended particles is permitted to flow under gravity out of the pan into a suitable receptacle. After the spent oil is removed, the plug is replaced and fresh oil is added to the engine through a separate opening in the engine valve cover. The process of gravity drainage does not remove all of the spent oil with its metallic and non-metallic particles which stick to the oil pan container walls, as well as engine components such as the crank shaft, connecting rods, pistons and the like which are exposed to the motor oil spray lubrication. These particles remain to be mixed with fresh motor oil Thus the concentration of contaminants is lowered by dilution and only a part of the total contaminates are actually eliminated.
Therefore, it would be desirable to provide a method which removes spent oil more completely and easily from the internal combustion engine. It would also be desirable to provide a system which reduces the amount of spent oil handling as required in the conventional oil change service method.
It is further desirable to provide an automated system that includes a source of compressed air and a means for supplying the compressed air for purging fluid from the internal combustion engine. It is finally desirable to provide a means for automatically sensing and controlling the air pressure inside the crankcase as well as deactivating the compressed air at a predetermined time to prevent over pressurizing of the crankcase and thereby adversely affecting the seals.